Copyright	(c) The University of Glasgow 1994-2000
License	see libraries/base/LICENSE
Maintainer	ghc-devs@haskell.org
Stability	internal
Portability	non-portable (GHC extensions)
Safe Haskell	Safe
Language	Haskell2010

GHC.Stats

Contents

Runtime statistics

Description

This module provides access to internal garbage collection and memory usage statistics. These statistics are not available unless a program is run with the -T RTS flag.

The API of this module is unstable and is tightly coupled to GHC's internals. If depend on it, make sure to use a tight upper bound, e.g., base < 4.X rather than base < 5, because the interface can change rapidly without much warning.

Since: base-4.5.0.0

Synopsis

data RTSStats = RTSStats {
- gcs :: Word32
- major_gcs :: Word32
- allocated_bytes :: Word64
- max_live_bytes :: Word64
- max_large_objects_bytes :: Word64
- max_compact_bytes :: Word64
- max_slop_bytes :: Word64
- max_mem_in_use_bytes :: Word64
- cumulative_live_bytes :: Word64
- copied_bytes :: Word64
- par_copied_bytes :: Word64
- cumulative_par_max_copied_bytes :: Word64
- cumulative_par_balanced_copied_bytes :: Word64
- init_cpu_ns :: RtsTime
- init_elapsed_ns :: RtsTime
- mutator_cpu_ns :: RtsTime
- mutator_elapsed_ns :: RtsTime
- gc_cpu_ns :: RtsTime
- gc_elapsed_ns :: RtsTime
- cpu_ns :: RtsTime
- elapsed_ns :: RtsTime
- nonmoving_gc_sync_cpu_ns :: RtsTime
- nonmoving_gc_sync_elapsed_ns :: RtsTime
- nonmoving_gc_sync_max_elapsed_ns :: RtsTime
- nonmoving_gc_cpu_ns :: RtsTime
- nonmoving_gc_elapsed_ns :: RtsTime
- nonmoving_gc_max_elapsed_ns :: RtsTime
- gc :: GCDetails
}
data GCDetails = GCDetails {
}
type RtsTime = Int64
getRTSStats :: IO RTSStats
getRTSStatsEnabled :: IO Bool

Runtime statistics

data RTSStats Source #

Statistics about runtime activity since the start of the program. This is a mirror of the C struct RTSStats in RtsAPI.h

Since: base-4.10.0.0

Constructors

RTSStats

Fields

gcs :: Word32
Total number of GCs
major_gcs :: Word32
Total number of major (oldest generation) GCs
allocated_bytes :: Word64
Total bytes allocated
max_live_bytes :: Word64
Maximum live data (including large objects + compact regions) in the heap. Updated after a major GC.
max_large_objects_bytes :: Word64
Maximum live data in large objects
max_compact_bytes :: Word64
Maximum live data in compact regions
max_slop_bytes :: Word64
Maximum slop
max_mem_in_use_bytes :: Word64
Maximum memory in use by the RTS
cumulative_live_bytes :: Word64
Sum of live bytes across all major GCs. Divided by major_gcs gives the average live data over the lifetime of the program.
copied_bytes :: Word64
Sum of copied_bytes across all GCs
par_copied_bytes :: Word64
Sum of copied_bytes across all parallel GCs
cumulative_par_max_copied_bytes :: Word64
Sum of par_max_copied_bytes across all parallel GCs. Deprecated.
cumulative_par_balanced_copied_bytes :: Word64
Sum of par_balanced_copied bytes across all parallel GCs
init_cpu_ns :: RtsTime
Total CPU time used by the init phase @since base-4.12.0.0
init_elapsed_ns :: RtsTime
Total elapsed time used by the init phase @since base-4.12.0.0
mutator_cpu_ns :: RtsTime
Total CPU time used by the mutator
mutator_elapsed_ns :: RtsTime
Total elapsed time used by the mutator
gc_cpu_ns :: RtsTime
Total CPU time used by the GC
gc_elapsed_ns :: RtsTime
Total elapsed time used by the GC
cpu_ns :: RtsTime
Total CPU time (at the previous GC)
elapsed_ns :: RtsTime
Total elapsed time (at the previous GC)
nonmoving_gc_sync_cpu_ns :: RtsTime
The total CPU time used during the post-mark pause phase of the concurrent nonmoving GC.
nonmoving_gc_sync_elapsed_ns :: RtsTime
The total time elapsed during the post-mark pause phase of the concurrent nonmoving GC.
nonmoving_gc_sync_max_elapsed_ns :: RtsTime
The maximum elapsed length of any post-mark pause phase of the concurrent nonmoving GC.
nonmoving_gc_cpu_ns :: RtsTime
The total CPU time used by the nonmoving GC.
nonmoving_gc_elapsed_ns :: RtsTime
The total time elapsed during which there is a nonmoving GC active.
nonmoving_gc_max_elapsed_ns :: RtsTime
The maximum time elapsed during any nonmoving GC cycle.
gc :: GCDetails
Details about the most recent GC

Instances

Instances details

Generic RTSStats

Instance details

Defined in GHC.Internal.Stats

Associated Types

type Rep RTSStats

Since: base-4.15.0.0

Instance details

Defined in GHC.Internal.Stats

Methods

from :: RTSStats -> Rep RTSStats x Source #

to :: Rep RTSStats x -> RTSStats Source #

Read RTSStats

Since: base-4.10.0.0

Instance details

Defined in GHC.Internal.Stats

Methods

readsPrec :: Int -> ReadS RTSStats Source #

readList :: ReadS [RTSStats] Source #

readPrec :: ReadPrec RTSStats Source #

readListPrec :: ReadPrec [RTSStats] Source #

Show RTSStats

Since: base-4.10.0.0

Instance details

Defined in GHC.Internal.Stats

Methods

showsPrec :: Int -> RTSStats -> ShowS Source #

show :: RTSStats -> String Source #

showList :: [RTSStats] -> ShowS Source #

type Rep RTSStats

Since: base-4.15.0.0

Instance details

Defined in GHC.Internal.Stats

data GCDetails Source #

Statistics about a single GC. This is a mirror of the C struct GCDetails in RtsAPI.h, with the field prefixed with gc_ to avoid collisions with RTSStats.

Constructors

GCDetails

Fields

gcdetails_gen :: Word32
The generation number of this GC
gcdetails_threads :: Word32
Number of threads used in this GC
gcdetails_allocated_bytes :: Word64
Number of bytes allocated since the previous GC
gcdetails_live_bytes :: Word64
Total amount of live data in the heap (includes large + compact data). Updated after every GC. Data in uncollected generations (in minor GCs) are considered live.
gcdetails_large_objects_bytes :: Word64
Total amount of live data in large objects
gcdetails_compact_bytes :: Word64
Total amount of live data in compact regions
gcdetails_slop_bytes :: Word64
Total amount of slop (wasted memory)
gcdetails_mem_in_use_bytes :: Word64
Total amount of memory in use by the RTS
gcdetails_copied_bytes :: Word64
Total amount of data copied during this GC
gcdetails_par_max_copied_bytes :: Word64
In parallel GC, the max amount of data copied by any one thread. Deprecated.
gcdetails_par_balanced_copied_bytes :: Word64
In parallel GC, the amount of balanced data copied by all threads
gcdetails_block_fragmentation_bytes :: Word64
The amount of memory lost due to block fragmentation in bytes. Block fragmentation is the difference between the amount of blocks retained by the RTS and the blocks that are in use. This occurs when megablocks are only sparsely used, eg, when data that cannot be moved retains a megablock.
Since: base-4.18.0.0
gcdetails_sync_elapsed_ns :: RtsTime
The time elapsed during synchronisation before GC
gcdetails_cpu_ns :: RtsTime
The CPU time used during GC itself
gcdetails_elapsed_ns :: RtsTime
The time elapsed during GC itself
gcdetails_nonmoving_gc_sync_cpu_ns :: RtsTime
The CPU time used during the post-mark pause phase of the concurrent nonmoving GC.
gcdetails_nonmoving_gc_sync_elapsed_ns :: RtsTime
The time elapsed during the post-mark pause phase of the concurrent nonmoving GC.